Thermal maturity of Codell Sandstone-Carlile Shale interval (Cretaceous) in part of Denver basin, Colorado

Conference · Fri Aug 01 04:00:00 EDT 1986 · Am. Assoc. Pet. Geol., Bull.; (United States)

OSTI ID:7053931

Ritchie, J G

Based on several geochemical parameters, hydrocarbons in the Codell Sandstone appear to have been derived from the underlying Carlile Shale. Both units are past peak thermal maturity and are at the upper limit of petroleum generation and preservation. The Turonian Codell Sandstone produces oil, gas, and condensate from wells drilled in the northwestern Denver basin. The zone of greatest thermal maturity follows the basin's north-northwest axis. Vitrinite reflectance (R/sub 0/) analyses reveal abundant weathered and reworked particles; R/sub 0/ values are 0.65 to 1.50% for the freshest, least altered particles. Pyrolysis analyses suggest thermal maturities near the upper limit for oil and gas generation and preservation. T/sub max/ values of 400/sup 0/C and bifurcated S/sub 2/ peaks are common. Data plotted on a modified van Krevelen diagram suggest that the Codell contains mainly Type III organic material and the Carlile more Type II material. This Type II organic matter may be the source for the Codell oil and gas. Genetic potential calculations for the Carlile samples support such a possibility. TTI calculations based on Lopatin diagrams predict that the Codell and Carlile lie within the liquid window. These TTI calculations correspond to lower geochemical parameters than those observed, suggesting that both the Codell and Carlile have passed peak thermal maturation.

• Research Organization: RPI Pacific, Redwood, City, CA
• OSTI ID: 7053931
• Report Number(s): CONF-8609129-
• Conference Information: Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Journal Volume: 70:8
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
CHEMISTRY
COLORADO
CRETACEOUS PERIOD
FEDERAL REGION VIII
GEOCHEMISTRY
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
MATURATION
MESOZOIC ERA
MINERAL RESOURCES
NATURAL GAS DEPOSITS
NORTH AMERICA
PETROLEUM DEPOSITS
RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SHALES
SOURCE ROCKS
USA